Q. I was reading an article online about the start stop feature cars use today to save on gas. This mechanic says it is the worst thing invented. Says everyone should disable this feature because it ruins your engine. Stating, starting an engine that many times shortens the life of the engine. Is there any real data about this feature? I really do not care for the feature myself but would like to know if it does save on gas and help the environment without shorting the life of the engine.
A. The starters are supposed to be more robust, if fact Toyota has a code for starter replacements and it is in the hundreds of thousands of starts. Chrysler and Hyundai both also claim the starting components are designed for repetitive start/stops. With today’s computer-controlled fuel injected engines there is very little chance of oil dilution, so I do not see this feature ruining an engine. Does it save on gas, yes it does, a little. About 11 years ago we did this study and found the tech does save fuel and lowers vehicle emissions. https://newsroom.aaa.com/2014/07/aaas-tests-reveal-real-world-benefits-automatic-stop-start-technology/. Is it my favorite new car feature, no. In fact the EPA is considering a ban on auto start/stop technology in new cars.
Q. I maintain my 2016 Honda Odyssey by the book hoping to drive it for 300,000 miles. At 104,000 miles I had the spark plugs changed. My gas mileage dropped from 27.8 mpg to 26.1 mpg under the same driving conditions. I asked my mechanic if there may be something that was not reconnected causing this 6% drop in mpg. He replied that there were many different things that could affect miles per gallon. Nothing else had or was changed. Thinking about this I decided to change the air filter. Now my MPG is back to my normal 27.8. Do you think that the hotter spark from new plugs may have required greater airflow for efficient combustion? It is recommended that the air filter be changed every 30,000 miles. I was going with the air filter manufacturer recommendation of 12 months. Which do you think is better? Also, for this test I purchased a Fram 18-month filter. Which brand filter do you prefer?
A. The idea that the filter improved the mileage is interesting, since technically the computer system should keep the fuel mixture the same-a clogged filter will reduce power which you need to add more throttle and end up using more fuel. Personally, I still look at the air filter and if it is dirty or dusty or pollen filled, I replace it. This is probably every 18 months of so. I try, when possible, to use factory filters or if not tend to use WIX filters which are made by Mann-Hummel. They also make many of the OE filters. Is Fram a good company I am sure, but I had a weird issue with a Fram oil filter on one car. I would get a lifter tap sound in the morning when I switched to the OE filter no tap. Since then, I have used WIX or the factory filter.
Q. My brand-new Kia K4 just turned 1500 miles and has an 8-speed automatic transmission with Normal setting and a Sport setting. I just went on a trip driving in a normal setting. On the highway at 70 MPH the tachometer is reading 2300 RPM’s. I discovered the car is in 7th gear. I can manually paddle shift to 8th gear and the RPM’s drop to 1600. On my trip there I did this all the time and got 45 MPG. On the way home I did not touch the paddles and got 38 MPG. Any thoughts?
A. This does sound a little strange. I can understand that in the sport setting, the computer will lock out 8th gear for better performance. In the normal setting they transmission should go into 8th speed at highway speeds. I would go back to the dealer and road test another K4 for comparison. Having an 8-speed transmission that does not shift into 8th gear automatically does not make much sense to me.
Q. I was watching YouTube and saw a mechanic checking for parasitic electrical drain with a thermal imaging camera. Does this work and have you tried it?
A. I recently have been using an Innova Infrared Inspection Camera. I did find a relay that stayed on when the car was off because of the heat signature. Although it is a versatile tool, it is not the quick answer to finding parasitic draw, it is just another tool for diagnostics and troubleshooting that can get you down the correct path. I think we watch the same channels.
Do you have car questions? Email AAA’s Car Doctor for a personal reply: jpaul@aaanortheast.com.
